A picture of U.S. President Barack Obama with a shoe on it lie on the ground in front of the former U.S. embassy during a gathering to mark the anniversary of freezing Iran and the U.S. diplomatic ties in Tehran April 9, 2009. The United States cut off diplomatic ties with Tehran during the 1979-1981 hostage crisis in which a group of militant Iranian students held 52 U.S. diplomats hostage at the American Embassy for 444 days. REUTERS/Stringer (IRAN POLITICS CONFLICT)